Typically, welded blade stabilizers are used in oil well drilling and blast hole drilling. In typical oil well drilling, drilling fluid is circulated downwardly through the drill string outwardly at the drill bit in order to circulate upwardly to the surface return drilling fluid containing drill cuttings so that the drill cuttings are continuously removed from the bottom of the hole. In blast hole drilling, the concept is essentially the same except that it is usually air that is circulated through the drill string and outwardly at the bit so that the return air circulating in the annular area between the drill string and the bore hole contains the cuttings which need to be circulated outwardly from the bottom of the hole. Welded blade stabilizers are used in both oil well drilling and blast hole drilling. A welded blade stabilizer generally includes a cylindrical body having multiple helically angled blades welded to the body. The stabilizer is mounted onto the drill string above the bit so that the welded-on blades may engage the side walls of the bore as freshly cut by the drill bit to further ream out the bore hole and stabilize the drill string and bit in position.
In such drilling operations such as blast hole drilling where air is used to circulate cuttings off of the bottom of the bore hole, a problem with prior art welded stabilizers is inhibited upward circulation of the return air and cuttings. Due to turbulence and restriction in the annular flow space caused by the stabilizer itself, it is known that air flow is inhibited and that drilling chips or cuttings may become stuck in the vicinity of the blades, thus preventing clear return circulation of the air and drill cuttings. The clogging of the drill cuttings in the area of the stabilizer blades causes the drill chips to fall back into the bit area and be reground. This regrinding slows down the drilling rate and decreases the life of the drill bit.